Kavli Affiliate: Chihway Chang
| First 5 Authors: Jazmine Jefferson, Yuuki Omori, Chihway Chang, Shrihan Agarwal, Joe Zuntz
| Summary:
In recent years, weak lensing shear catalogs have been released by various
Stage-III weak lensing surveys including the Kilo-Degree Survey, the Dark
Energy Survey, and the Hyper Suprime-Cam Subaru Strategic Program. These shear
catalogs have undergone rigorous validation tests to ensure that the residual
shear systematic effects in the catalogs are subdominant relative to the
statistical uncertainties, such that the resulting cosmological constraints are
unbiased. While there exists a generic set of tests that are designed to probe
certain systematic effects, the implementations differ slightly across the
individual surveys, making it difficult to make direct comparisons. In this
paper, we use the TXPipe package to conduct a series of predefined diagnostic
tests across three public shear catalogs — the 1,000 deg$^2$ KiDS-1000 shear
catalog, the Year 3 DES-Y3 shear catalog, and the Year 3 HSC-Y3 shear catalog.
We attempt to reproduce the published results when possible and perform key
tests uniformly across the surveys. While all surveys pass most of the null
tests in this study, we find two tests where some of the surveys fail. Namely,
we find that when measuring the tangential ellipticity around bright and faint
star samples, KiDS-1000 fails depending on whether the samples are weighted,
with a $chi^2$/dof of 185.3/13 for faint stars. We also find that DES-Y3 and
HSC-Y3 fail the $B$-mode test when estimated with the Hybrid-$E$/$B$ method,
with a $chi^2$/dof of 37.9/10 and 36.0/8 for the fourth and third
autocorrelation bins. We assess the impacts on the $Omega_{rm m}$ – S$_{8}$
parameter space by comparing the posteriors of a simulated data vector with and
without PSF contamination — we find negligible effects in all cases. Finally,
we propose strategies for performing these tests on future surveys such as the
Vera C. Rubin Observatory’s Legacy Survey of Space and Time.
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